Human resistivity sensing device

ABSTRACT

An electrical circuit which is capable of producing a varying signal output, either in frequency or amplitude which is responsive to the changing resistivity sensed on the skin of a subject. Electrodes are placed on the subject&#39;&#39;s body and as the surface resistance changes, an audible signal is produced which can aid the subject in relaxing.

United States Patent 11 1 Taaffe HUMAN RESISTIVITY SENSING DEVICEInventor: James L. Taaffe, Philadelphia, Pa, Assignee: Phillip Brotman,New York, N.Y,

Filed: Mar. 26, I973 Appl. No: 344,650

US. Cl. [ZS/2.1 Z; 324/62 R Int. Cl A6lb 5/05 Field of Search 128/21 Z,241 R, 2.06 R;

References Cited UNITED STATES PATENTS Mathison 128/21 Z Mathison it128/21 Z Wcidingcr ct a1 U 128/206 R [4 1 Aug. 26, 1975 3,426,150 2/1969Tygart 128/2106 R 3,556,083 [/1971 Grichnik 128/21 Z 3,614,651 10/1971Pasquier 128/21 R 3,648,686 3/1972 Payne 128/21 Z PrimaryExaminer-Richard A. Gaudet Assistant Examiner-Lee S. Cohen Attorney,Agent, or Firm-Peter L. Berger 1 1 ABSTRACT An electrical circuit whichis capable of producing a varying signal output, either in frequency oramplitude which is responsive to the changing resistivity sensed on theskin of a subject. Electrodes are placed on the subject's body and asthe surface resistance changes, an audible signal is produced which canaid the subject in relaxing.

2 Claims, I Drawing Figure HUMAN RESISTIVITY SENSING DEVICE Thisinvention relates to a bio-feedback type device used to gauge the levelof tension of a subject.

It is proposed to provide a unique and improved electrical circuithaving extremely good reliability and good utilization to sense theanxiety levels of a subject by producing an audible sound which isreflective of the subjects state. Biasing means are provided to set anorm about which the audible tone will vary.

The attached FIGURE illustrates an embodiment of this invention.

The electrical circuit is comprised of electrodes and 12 attached to agripping member 14 which is capable of being either in a flat positionso as to be attached to a flat surface of the body, or circular so as tobe attached to an extremity. Electrode 10 is connected to the base of atransistor 16 through a resistor 18 and through a fixed resistor 20 anda biasing resistor 22 to the emitter of transistor 16. The collector ofthe transistor is connected through a resistor 24 to an emitter terminalof a unijunction transistor 26 as well as to one end of a capacitor 28,the other end of which is connected to ground. One base terminal of theunijunction transistor is connected through a resistor 30 to one end ofa speaker 32 coil 34 and to the emitter of transistor 16. The other endof speaker coil 34 is connected to the collector ofa transistor 36, theemitter of which is connected to ground while the base thereof isconnected to the second base terminal of unijunction transistor 26.

The circuit functions in the following manner: electrodes 10 and 12connect to various places on the skin of the body. The person using theinstrument adjusts the range or biasing control by varying resistance 22to a desired tone, such as many-frequency. As his body resistancedecreases, the frequency of the tone increases thus signalling greateranxiety for lesser body resistance. Capacitor 28 is charged throughtransistor 16 at a rate controlled by resistor 22 which controls theamount of current produced by current source means formed by transistor16. Unijunction transistor 26 is a triggering device which is caused totrigger when its threshold rate is reached. The rate at which the levelis reached is set by biasing resistor 22 but will be varied as the bodyresistance sensed at electrodes 10 and l2 varies. This is due to thevoltage divider formed by the body resistance and resistors 20 and 22.

The output of unijunction transistor 26 is coupled through amplifiermeans formed by transistor 36 to energize speaker 32 so as to produce anaudible sound.

I claim:

1. Electrical circuit means capable of being connected to the human bodyand producing a changing signal in response to changes in the surfaceresistivity of the human skin comprising electrode means adapted to beplaced on the skin, variable frequency means comprising a unijunctiontransistor having an emitter and a pair of base terminals, biasing meansconnected between said electrode means and said variable frequency meansfor setting a biasing level for said variable frequency means, saidemitter being connected to said biasing means,

said biasing means comprising a transistor and a variable resistancecontrolling the amount of current produced by said transistor,

said transistor having a base resistor connected thereto, said electrodemeans being connected through said base resistor to the input of saidtransistor to control the amount of current produced thereby,

a collector resistor connected to the collector of said transistor, acapacitor connected through said collector resistor to receive saidcurrent of said transistor to be charged thereby, said capacitorconnected to said emitter of said unijunction transistor to cause saidunijunction transistor to be triggered into conduction,

said variable resistance and the resistance at the electrode meansforming a voltage divider,

the connection between said voltage divider connected to said transistorthrough said base resistor and,

speaker means connected to receive the output of said variable frequencymeans to produce an audible signal representation of the frequency ofthe signal produced by said variable frequency means.

2. Electrical circuit means as set forth in claim 1, comprisingamplifier means connected between the output of said unijunctiontransistor and said speaker means.

1. Electrical circuit means capable of being connected to the human bodyand producing a changing signal in response to changes in the surfaceresistivity of the human skin comprising electrode means adapted to beplaced on the skin, variable frequency means comprising a unijunctiontransistor having an emitter and a pair of base terminals, biasing meansconnected between said elEctrode means and said variable frequency meansfor setting a biasing level for said variable frequency means, saidemitter being connected to said biasing means, said biasing meanscomprising a transistor and a variable resistance controlling the amountof current produced by said transistor, said transistor having a baseresistor connected thereto, said electrode means being connected throughsaid base resistor to the input of said transistor to control the amountof current produced thereby, a collector resistor connected to thecollector of said transistor, a capacitor connected through saidcollector resistor to receive said current of said transistor to becharged thereby, said capacitor connected to said emitter of saidunijunction transistor to cause said unijunction transistor to betriggered into conduction, said variable resistance and the resistanceat the electrode means forming a voltage divider, the connection betweensaid voltage divider connected to said transistor through said baseresistor and, speaker means connected to receive the output of saidvariable frequency means to produce an audible signal representation ofthe frequency of the signal produced by said variable frequency means.2. Electrical circuit means as set forth in claim 1, comprisingamplifier means connected between the output of said unijunctiontransistor and said speaker means.